1. Field of the Invention
The present invention relates to endoscope optical systems and endoscopes.
2. Description of Related Art
In known endoscopes in the related art, the viewing direction of the endoscope can be changed by swiveling or rotating a prism disposed in a tip portion of the endoscope to change the orientation of the distal end face thereof (for example, see U.S. Pat. No. 6,638,216 and Japanese Unexamined Patent Application, Publication No. 2006-201796).
In the endoscope disclosed in U.S. Pat. No. 6,638,216, the prism is disposed at a position shifted in the diameter direction from the optical axis of other optical systems inside the endoscope and moves in the diameter direction inside the endoscope.
In the endoscope disclosed in Japanese Unexamined Patent Application, Publication No. 2006-201796, the prism is disposed so as to protrude in the diameter direction from the tip portion of the endoscope, and the optical axis of an optical system from the prism to an image sensor is orthogonal to the optical axis of the main endoscope body.